If you're trying to use a delegate from C, you need to be aware of the delegate's target, which is a hidden parameter to Vala code but visible in C.
If you compile your code with the --save-temps flag enabled, you can see how a delegate is constructed in C. For example: delegate void Callback(int32 i); Becomes this in the .c: typedef void (*Callback) (gint32 i, void* user_data); The user_data is the target (in Vala-parlance). Your C code should invoke the callback like this: Callback _cb = cb; ... _cb (i, obj); Rob's right, you can't (or shouldn't) assign to "this" in Vala. When you invoke the callback with obj as the user_data, Vala's internal code will use it as the "this" reference. A useful reference if you're making a VAPI: http://live.gnome.org/Vala/Bindings/MetadataFormat -- Jim On Tue, Sep 28, 2010 at 5:10 AM, Cyrille Colin <co...@univ-metz.fr> wrote: > hi, > i've just update to 0.10 from 0.8.1 and I guess now vala detect one of > my bad. > I used a init function to give my object pointer to external function > that will manage callback : > > init(this) > > init() is define in a vapi : > public static void init (ValaObj obj); > > and use in External library like this : > > static void *ValaObj; > void init (void *obj) { > ValaObj = obj; > } > > Then i define in vapi the callback, C -> Vala : > public delegate uint32 callback ( ValaObj, int value); > > and this is my callback in Vala code: > public uint32 cb (ValaObj obj, int value) { > this = obj; > ... > } > it works fine with 0.8.1 and throw exception with 0.10 : > error: unsupported lvalue in assignment > May someone could help me, > thanks in advance, > Cyrille. > > > > > _______________________________________________ > vala-list mailing list > vala-list@gnome.org > http://mail.gnome.org/mailman/listinfo/vala-list >
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